This project focuses on the behavioral neurophysiology of the frontal lobe of primates. Through the development of a number of novel behavioral methods, we have begun to distinguish neuronal signals reflecting sensory and perceptual processes from those involving the selection and control of motor behavior. We have found that the former predominate in prefrontal cortex, whereas the later can be most often identified in the premotor cortex. We have focused on two kinds of rules in a study of motor learning: conditional motor rules and skills. During the past year we have begun projects that aim to identify neural signals reflecting behavior-guiding rules in the prefrontal cortex and to distinguish the mechanisms of visual perception from those of visually guided action. We have also been engaged in the writing of several scholarly reviews on the subject of this project and its relation to cognate fields.